The present invention relates to a quick-action tensioning device for cable control switches. The tensioning device has a holding element, to which a cable can be fastened in a clamping manner, and has a housings, which is connected with the holding element.
Quick-action tensioning devices for cable control switches exist in which the cable can be fastened between two clamping jaws, a movement of the cable in one direction being permitted as a result of the clamping jaws. Such a quick-action tensioning device is relatively comfortable to mount because the cable is pulled in the desired position and fixed. However, no precision adjustment is provided after an adjusting of the cable. Such quick-action tensioning devices are usually used in connection with cable control switches which are used in different environments, so that a lengthening or shortening of the cable can take place as a result of thermal influences. If such a change of the cable length cannot also be adjusted for by the quick-action tensioning device, the cable control switch may be triggered too early or too late, which would result in considerable danger.
The present invention relates to a quick-action tensioning device for cable control switches which permits a rough adjustment as well as a precision adjustment.
The present invention then is a quick-action tensioning device for cable control switches. The tensioning device includes a holding element to which a cable is fastened in a clamping manner. Also included is a housing connected with the holding element. A first device and a second device are provided between the housing and the holding element for precisely adjusting a distance between the housing and the holding element.
Since the quick-action tensioning device has precision adjusting devices between the housing and the holding element, the cable can first be clampingly fixed to the holding element, whereby a rough adjustment can be carried out. Should the cable length change as a result of thermal lengthening or shortening or because of expansion phenomena, a precision adjusting can be carried out. Therefore, the triggering of the cable control switch may always take place at a desirable point.
According to a preferred embodiment of the present invention, a threaded shaft is provided between the housing and the holding element. The distance between the housing and the holding element being adjustable by a nut. As a result, a continuous adjustment of the cable tension can be carried out. The nut is preferably constructed as a knurled nut, so that the precision adjusting can take place without any tool.
A device for detecting the cable tension is preferably provided in the housing. Since usually a certain force has to be overcome for the operation of a switch, the cable should initially have a certain tension in order to ensure a secure triggering. Accordingly, a display for the cable tension is provided at the housing, so that the precision adjusting can take place without any additional measuring of the cable tension, because the cable tension is shown by the display. Even small changes in the length of the cable can be detected.
For a secure fastening of the cable, the holding element has a plate so that the cable can be clamped between the plate and a body of the holding element. The cable is preferably deflected between the plate and the body, so that substantially high friction forces occur as a result of the clamping. The high friction forces can be absorbed by the quick-action tensioning device for cable control switches. The invention will be better understood and appreciated from the following detailed descriptions and with reference to the accompanying drawings.